6. When the people who answer a mail survey are different in important ways (e.g., income level) from
the people who did not answer the survey, the survey is said to have ____________________ error.
7. People who are cannot be contacted or who refuse to participate in a survey are called
____________________.
8. A person who is not at home when an interviewer calls is called a(n) ____________________.
9. A person hangs up the phone when he is asked to answer a few questions about his television viewing
habits because he is not interested in participating in the study. This behavior is called a(n)
____________________.
10. If the interviewer’s presence influences respondents to give untrue or modified answers, the survey
will be marred by ____________________.
11. When a mistake is made in carrying out the design of a research study, ____________________ error
has occurred.
12. When an interviewer does not record the respondent’s answers correctly, ____________________
error has occurred.
13. An attempt to re-contact a potential respondent in a phone survey when no one answered the phone on
a previous attempt is called a(n) ____________________.